The acoustic properties of bilingual infant-directed speech

Abstract

Does the acoustic input for bilingual infants equal the conjunction of the input heard by monolinguals of each separate language? The present letter tackles this question, focusing on maternal speech addressed to 11-month-old infants, on the cusp of perceptual attunement. The acoustic characteristics of the point vowels /a,i,u/ were measured in the spontaneous infant-directed speech of French-English bilingual mothers, as well as in the speech of French and English monolingual mothers. Bilingual caregivers produced their two languages with acoustic prosodic separation equal to that of the monolinguals, while also conveying distinct spectral characteristics of the point vowels in their two languages.

Input quality and speech perception development in bilingual infants’ first year of life

“…This would provide the first evidence for this acoustic adjustment in Basque IDS. Comparable degrees of vowel exaggeration in Spanish and Basque and in caregivers of monolingual and bilingual 5‐ and 9‐month‐old infants would support the view that this adjustment is manifested across a variety of languages and is independent of infants’ age (Kalashnikova & Burnham, 2018; Liu et al, 2009), and that phonetic properties of bilingual and monolingual caregivers’ IDS are comparable (Danielson et al, 2014). Furthermore, individual indices of acoustic vowel exaggeration in IDS were expected to relate to infants’ native speech discrimination abilities across the entire sample including monolingual and bilingual infants (Garcia‐Sierra et al, 2021; Liu et al, 2003).…”

A Multilab Study of Bilingual Infants: Exploring the Preference for Infant-Directed Speech

“…Bilingual infants often have bilingual caregivers, and even when they are highly proficient speakers, their speech may vary from that of monolinguals. One study compared vowels produced in the IDS of monolingual English, monolingual French, and balanced French-English bilingual mothers living in Montreal (Danielson et al, 2014). Bilingual mothers’ vowels were distinct in the two languages, and the magnitude of the difference between French and English vowels was similar to that shown by monolingual mothers.…”

Languages As Categories: Reframing the “One Language or Two” Question in Early Bilingual Development

“…Further, they are sensitive to phonetic information (Sundara, Polka, & Molnar, ) and phonotactic distinctions that could also support language discrimination (Sebastián‐Gallés & Bosch, ). It is likely that bilingual infants are also sensitive to other perceptual differences between their languages that have not yet been enumerated (see Kyle Danielson, Seidl, Onishi, Alamian, & Cristià, , for a study of acoustic information available in bilingual infant‐directed speech). These perceptual sensitivities could support early perceptual language categories, which would be foundational for the development of conceptual language categories.…”